You live on a busy street, but as a music lover, you want to reduce the traffic noise. If you install special sound-reflecting windows that reduce the sound intensity level (in dB) by 30 dB, by what fraction have you lowered the sound intensity $(i n \frac{w}{m^{2}})$ ?

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Solution

The correct option is A

Let the initial intensity be $I_{1}$

Corresponding initial intensity level will be

$β_{1} = 10 l o g (\frac{I_{2}}{I_{0}})$

Now you have to reduce intensity level by 30 dB

$β_{2} = 10 l o g \frac{I_{2}}{I_{0}}$

we know $β_{1} - β_{2} = 30 = 10 l o g \frac{I_{1}}{I_{0}} - 10 l o g \frac{I_{2}}{I_{0}}$

$\Rightarrow 30 = 10 l o g (\frac{I_{1}}{I_{0}})$

$\frac{I_{1}}{I_{2}} = 10^{3}$

$\frac{I_{2}}{I_{1}} = 10^{- 3}$

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Similar questions

You live on a busy street, but as a music lover, you want to reduce the traffic noise. If you install special sound-reflecting windows that reduce the sound intensity level (in dB) by 30 dB, by what fraction have you lowered the sound intensity $(i n \frac{w}{m^{2}})$ ?

Q. A sound has an intensity of

3 \times 10^{- 8} W / m^{2}

. What is the sound level in dB (decibels)? (Given,

l o g 3 = 0.477

)

Q. A small speaker delivers

2 W

of audio output. At what distance from the speaker will one detect

120 dB

intensity sound? [Given reference intensity of sound as

10^{- 12} {W/m}^{2}]

Decibel (dB) is a unit of loudness of sound. It is defined in a manner such that when the amplitude of the sound is multiplied by a factor of $\sqrt{10}$ , the decibel level increases by 10 units. Loud music of 70dB is being played at a function. To reduce the loudness to a level of 30dB, the amplitude of the instrument playing music has to be reduced by a factor of:

What do you understand by the intensity of sound? [1 MARK]

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You live on a busy street, but as a music lover, you want to reduce the traffic noise. If you install special sound-reflecting windows that reduce the sound intensity level (in dB) by 30 dB, by what fraction have you lowered the sound intensity (inwm2)?

The correct option is A Let the initial intensity be I1 Corresponding initial intensity level will be β1 = 10 log (I2I0) Now you have to reduce intensity level by 30 dB β2 = 10 log I2I0 we know β1 − β2 = 30 = 10 logI1I0 − 10 log I2I0 ⇒ 30 = 10 log(I1I0) I1I2 = 103 I2I1 = 10−3

You live on a busy street, but as a music lover, you want to reduce the traffic noise. If you install special sound-reflecting windows that reduce the sound intensity level (in dB) by 30 dB, by what fraction have you lowered the sound intensity $(i n \frac{w}{m^{2}})$ ?